Illinois Population By County in 2017

Updated on January 29, 2024.

Based on the US Census Vintage data estimates, in 2017, the population of Illinois was 12,779,893. Among all Illinois counties, Cook had the highest population (5,199,582), followed by DuPage (930,569), and Lake (702,825). Hardin was the least populated county (3,920).

Hover over or click on the counties in the map below to see the populations. The data can also be found in a table below. You can use the table to sort, filter, and explore the data further.

You can see similar information for other states and by state for the United States.

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Illinois Population By County in 2017
Illinois Population By County in 2017
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County Population % of State Population
Adams 66073 0.52
Alexander 6276 0.05
Bond 16654 0.13
Boone 53481 0.42
Brown 6614 0.05
Bureau 33134 0.26
Calhoun 4847 0.04
Carroll 14473 0.11
Cass 12525 0.10
Champaign 210630 1.65
Christian 33045 0.26
Clark 15824 0.12
Clay 13259 0.10
Clinton 37649 0.30
Coles 51403 0.40
Cook 5199582 40.69
Crawford 18979 0.15
Cumberland 10887 0.09
DeKalb 104513 0.82
De Witt 15910 0.12
Douglas 19616 0.15
DuPage 930569 7.28
Edgar 17415 0.14
Edwards 6455 0.05
Effingham 34165 0.27
Fayette 21537 0.17
Ford 13291 0.10
Franklin 39024 0.31
Fulton 35099 0.28
Gallatin 5073 0.04
Greene 13153 0.10
Grundy 50627 0.40
Hamilton 8192 0.06
Hancock 17959 0.14
Hardin 3920 0.03
Henderson 6824 0.05
Henry 49222 0.39
Iroquois 27780 0.22
Jackson 57973 0.45
Jasper 9504 0.07
Jefferson 38059 0.30
Jersey 21892 0.17
Jo Daviess 21509 0.17
Johnson 12394 0.10
Kane 532101 4.16
Kankakee 110530 0.87
Kendall 126163 0.99
Knox 50601 0.40
Lake 702825 5.50
LaSalle 109590 0.86
Lawrence 16025 0.13
Lee 34533 0.27
Livingston 36080 0.28
Logan 29035 0.23
McDonough 30419 0.24
McHenry 307842 2.41
McLean 172769 1.35
Macon 105474 0.83
Macoupin 45521 0.36
Madison 265516 2.08
Marion 37757 0.30
Marshall 11667 0.09
Mason 13672 0.11
Massac 14298 0.11
Menard 12311 0.10
Mercer 15618 0.12
Monroe 34261 0.27
Montgomery 28781 0.23
Morgan 34275 0.27
Moultrie 14704 0.12
Ogle 51021 0.40
Peoria 182657 1.43
Perry 21292 0.17
Piatt 16427 0.13
Pike 15669 0.12
Pope 4193 0.03
Pulaski 5531 0.04
Putnam 5696 0.05
Randolph 32258 0.25
Richland 15842 0.12
Rock Island 143824 1.13
St. Clair 262881 2.06
Saline 23968 0.19
Sangamon 197163 1.54
Schuyler 6984 0.06
Scott 4983 0.04
Shelby 21773 0.17
Stark 5459 0.04
Stephenson 44998 0.35
Tazewell 133525 1.05
Union 16982 0.13
Vermilion 77722 0.61
Wabash 11466 0.09
Warren 17133 0.13
Washington 13960 0.11
Wayne 16435 0.13
White 13898 0.11
Whiteside 56009 0.44
Will 690356 5.40
Williamson 67076 0.53
Winnebago 284658 2.23
Woodford 38676 0.30